Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 1st Term
Week: 3
Age: 15 years
Duration: 45 minutes
Subject: Basic Electricity
Curriculum Theme: Basic Electricity
Previous Lesson: Conductors and Insulators.
Topic: Ohm’s Law
Subject Matter: Statement of Ohm’s Law, relationship between current voltage and resistance, use of formula V equals I R, experimental verification of Ohm’s Law.

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

Define Ohm’s Law.
State the formula for Ohm’s Law.
Explain the relationship between current, voltage, and resistance.
Solve simple problems involving Ohm’s Law.

Affective Domain:

Appreciate the importance of Ohm’s Law in electrical circuits.
Show interest in conducting experiments related to electricity.

Psychomotor Domain:

Draw a simple circuit diagram for verifying Ohm’s Law.
Conduct an experiment to verify Ohm’s Law.
Calculate resistance from experimental data.

Collaborate effectively with peers during practical activities.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum (Senior Secondary School Physics)
State Unified Scheme of Work for Senior Secondary Schools
New Concept Physics for Senior Secondary Schools by P.N. Okeke et al.
https://www.physicsclassroom.com/class/circuits/Lesson-3/Ohm-s-Law
https://www.fluke.com/en-us/learn/blog/electrical/what-is-ohms-law

Instructional Materials

The teacher will teach this lesson with the aid of:

DC power supply
Ammeter
Voltmeter
Connecting wires
Resistors
Circuit board
Chalkboard/Whiteboard

Rationale for the Lesson

This lesson helps pupils understand the fundamental relationship between voltage, current, and resistance in an electrical circuit. It enables them to predict how changes in one quantity affect the others, which is important for understanding how electrical devices work in daily life.

Prerequisite/Previous Knowledge

Pupils have prior knowledge of basic electrical concepts such as electric current, voltage (potential difference), and resistance from previous lessons.

Lesson Content/Board Summary

Ohm’s Law

Statement of Ohm’s Law

Ohm’s Law states that the current (I) flowing through a metallic conductor is directly proportional to the potential difference (V) across its ends, provided the temperature and other physical conditions remain constant.

Relationship between Current, Voltage, and Resistance

In a circuit, voltage, current, and resistance are related as follows:

Current is directly proportional to voltage (I ∝ V). This means if voltage increases, current increases, and vice versa.
Current is inversely proportional to resistance (I ∝ 1/R). This means if resistance increases, current decreases, and vice versa.

Ohm’s Law Formula

The mathematical expression for Ohm’s Law is:

V = I R

Where:

V = Voltage (Potential Difference) in Volts (V)
I = Current in Amperes (A)
R = Resistance in Ohms (Ω)

From this formula, current and resistance can also be calculated:

I = V / R
R = V / I

Experimental Verification of Ohm’s Law

Ohm’s Law can be verified experimentally by setting up a simple circuit and observing the relationship between voltage and current across a resistor.

The steps to verify Ohm’s Law experimentally are:

Connect a DC power supply, an ammeter (in series), a voltmeter (in parallel across the resistor), and the resistor using connecting wires on a circuit board.
Vary the voltage across the resistor using the power supply.
For each voltage setting, record the corresponding current reading from the ammeter and the voltage reading from the voltmeter.
Plot a graph of voltage (V) on the y-axis against current (I) on the x-axis.
A straight line passing through the origin indicates that V is directly proportional to I, thus verifying Ohm’s Law. The slope of this graph gives the resistance (R).

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and reminds them of the previous lesson on basic electrical quantities like current, voltage, and resistance. The teacher then asks pupils to recall the units of these quantities.
Pupils’ Activity: Pupils respond to the teacher’s questions and recall the units of current, voltage, and resistance.
Learning Point: Pupils recall prior knowledge related to the topic.

Step 2: Statement of Ohm’s Law

Time: 7 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher introduces the topic “Ohm’s Law” and writes it on the board. The teacher then states Ohm’s Law clearly, explaining the conditions under which it applies (constant temperature).
Pupils’ Activity: Pupils listen attentively, copy the definition into their notebooks, and ask clarifying questions.
Learning Point: Pupils understand the statement and conditions of Ohm’s Law.

Step 3: Relationship between Current, Voltage, and Resistance & Formula

Time: 8 minutes
Teaching Skill: Explanation/Derivation
Teacher’s Activity: The teacher explains the direct proportionality between voltage and current, and the inverse proportionality between current and resistance. The teacher then introduces the formula V = IR, explaining each symbol and its unit. The teacher also shows how to derive I = V/R and R = V/I.
Pupils’ Activity: Pupils observe, listen, and copy the relationships and formulas into their notebooks.
Learning Point: Pupils understand the mathematical representation of Ohm’s Law and its components.

Step 4: Problem Solving with Ohm’s Law

Time: 5 minutes
Teaching Skill: Application/Demonstration
Teacher’s Activity: The teacher solves a simple calculation problem on the board using the Ohm’s Law formula to find an unknown quantity (e.g., current, voltage, or resistance) when the other two are given.
Pupils’ Activity: Pupils observe the problem-solving steps and ask questions for clarity.
Learning Point: Pupils learn to apply Ohm’s Law to solve numerical problems.

Step 5: Experimental Setup for Verification

Time: 8 minutes
Teaching Skill: Demonstration/Practical
Teacher’s Activity: The teacher displays the instructional materials (DC power supply, ammeter, voltmeter, resistor, wires, circuit board). The teacher then demonstrates how to connect the components to form a circuit to verify Ohm’s Law, emphasizing the correct connection of the ammeter (series) and voltmeter (parallel).
Pupils’ Activity: Pupils observe the teacher’s demonstration carefully and identify the components.
Learning Point: Pupils understand the practical setup for verifying Ohm’s Law.

Step 6: Data Collection and Observation

Time: 7 minutes
Teaching Skill: Observation/Guided Practice
Teacher’s Activity: The teacher guides the pupils through varying the voltage and taking readings from the ammeter and voltmeter. The teacher records the readings in a table on the board. The teacher then explains how plotting V against I will yield a straight line, confirming Ohm’s Law.
Pupils’ Activity: Pupils observe the readings, discuss the expected outcome, and note down the data.
Learning Point: Pupils learn how to collect data and interpret results for Ohm’s Law verification.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

State Ohm’s Law.
Write the formula for Ohm’s Law and state the units of each quantity.
If the voltage across a resistor is 12V and the current flowing through it is 2A, what is the resistance of the resistor?
Mention two components needed to set up a circuit for verifying Ohm’s Law.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 3 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the statement of Ohm’s Law, its formula, and its experimental verification. The teacher assigns homework: “Draw a circuit diagram for verifying Ohm’s Law and label the components.”
Pupils’ Activity: Pupils listen to the summary and copy the homework assignment.
Learning Point: Pupils consolidate their learning and prepare for further study.

Lesson Keywords

Ohm’s Law – A law stating that current is directly proportional to voltage and inversely proportional to resistance.
Voltage (V) – The potential difference across two points in a circuit, measured in Volts.
Current (I) – The flow of electric charge, measured in Amperes.
Resistance (R) – The opposition to the flow of electric current, measured in Ohms.
Ammeter – An instrument used to measure electric current.
Voltmeter – An instrument used to measure potential difference (voltage).

Differentiation

For pupils who grasp concepts quickly, the teacher can provide more complex problems involving series and parallel circuits. For pupils needing more support, the teacher can provide additional guided practice with simpler calculations and direct supervision during the experimental setup.

Note for teachers using this lesson plan

Ensure all instructional materials are available and in good working condition before the lesson. Emphasize safety precautions when handling electrical components. Encourage active participation and questions from pupils to ensure clarity and understanding.